Research
Hydroxytyrosol
44 peer-reviewed studies curated from PubMed and Semantic Scholar.
Studies
Sorted by quality and recency
Neuroprotective effects of olive oil and its phenolic compounds on neuroinflammation: a systematic review.
Systematic review of 32 preclinical in vivo studies assessing the effects of olive oil and its phenolic compounds on neuroinflammation. Olive oil, especially extra-virgin olive oil rich in phenolic compounds, showed anti-inflammatory effects, with hydroxytyrosol being the most effective compound. Variability in study design and lack of pharmacokinetic data limit translational interpretation.
The potential preventive role of a dietary supplement containing hydroxytyrosol in COVID-19: a multi-center study.
A multi-center RCT involving 443 subjects from Albania, Germany, and Italy tested a dietary supplement containing hydroxytyrosol (HT) against a placebo for one month. The HT group had a significantly lower rate of COVID-19 infection (36%) compared to the placebo group (64%), suggesting a potential preventive effect of HT against COVID-19.
Evaluation of the effect of olive extracts on blood pressure and cardiovascular health markers in adults: Findings from a double-blind, placebo-controlled, randomised trial.
Double-blind, placebo-controlled RCT of 56 adults with systolic blood pressure ≥130 mmHg, testing 440 mg olive dry extract supplementation over eight weeks. Both intervention and control groups showed reductions in systolic blood pressure and lipid levels, but no significant differences between groups were observed. Olive extract was well-tolerated, but no significant hypotensive benefit was found.
Hydroxytyrosol supplementation improves antioxidant and anti-inflammatory status in individuals with overweight and prediabetes: A randomized, double-blind, placebo-controlled parallel trial.
A randomized, double-blind, placebo-controlled trial investigated the effects of 15 mg/day hydroxytyrosol supplementation for 16 weeks in overweight individuals with prediabetes. The study found significant improvements in antioxidant and anti-inflammatory status, including reduced oxLDL, protein carbonyls, and IL-6 levels, suggesting a potential preventive role against aging-related diseases.
Multi-omic analysis and platelet function distinguish treatment responses to hydroxytyrosol in cardiovascular risk.
The study investigated the effects of hydroxytyrosol (HT) on cardiovascular risk patients, distinguishing between HT responders and non-responders. HT intervention suppressed platelet reactivity and altered microbiota composition, with improved glutathione metabolism observed in responders.
Hydroxytyrosol Improves Metabolic Dysfunction-Associated Fatty Liver Disease Dependent on the Modulation of Gut Microbiota.
An 8-week randomized placebo-controlled clinical trial investigated the effects of hydroxytyrosol on metabolic dysfunction-associated fatty liver disease (MAFLD) and gut microbiota. Hydroxytyrosol mitigated liver injury, steatosis, and systemic glucolipid metabolism disorder in MAFLD patients. Fecal microbiota transplantation in mice confirmed the role of gut microbiota changes in improving MAFLD phenotypes.
Effects of Desert Olive Tree Pearls Containing High Hydroxytyrosol Concentrations on the Cognitive Functions of Middle-Aged and Older Adults.
RCT examining the effects of desert olive tree pearls (DOTPs) containing high hydroxytyrosol concentrations on cognitive function in middle-aged and older adults. Significant improvements were observed in complex attention, psychomotor speed, reaction time, cognitive flexibility, processing speed, and executive function domains.
The Short-Term Effect of Olive Oil Extract Enriched with Hydroxytyrosol on Cardiovascular Function.
This randomized crossover study examined the short-term effects of olive oil extract enriched with hydroxytyrosol on cardiovascular function in 61 patients with chronic coronary artery disease. While no significant changes were observed in several cardiovascular parameters, there was a trend toward improvement in left ventricular diastolic function and aortic elastic properties.
Oral Supplement Containing Hydroxytyrosol and Punicalagin Improves Dyslipidemia in an Adult Population without Co-Adjuvant Treatment: A Randomized, Double-Blind, Controlled and Crossover Trial.
A randomized, double-blind, controlled, crossover trial evaluated the effect of an oral supplement containing hydroxytyrosol and punicalagin on dyslipidemia in adults. The supplement significantly reduced triglycerides and LDL-C levels while increasing HDL-C levels, demonstrating antiatherosclerotic and cardioprotective effects.
Effects of a Combination of Extracts from Olive Fruit and Almonds Skin on Oxidative and Inflammation Markers in Hypercholesterolemic Subjects: A Randomized Controlled Trial.
RCT evaluating the effect of olive fruit and almond skin extracts on LDL cholesterol oxidation and inflammatory markers in adults with moderate hypercholesterolemia. The extract group showed lower oxidized LDL levels and improved inflammatory markers compared to placebo.
Antioxidant activity of Hydroxytyrosol and Vitamin E reduces systemic inflammation in children with paediatric NAFLD.
RCT investigating the effects of Hydroxytyrosol and Vitamin E on systemic inflammation in children with NAFLD. The treatment reduced levels of IL-6 and increased IL-10, correlating with improvements in steatosis and triglyceride levels.
Anti-cancer properties of olive oil secoiridoid phenols: a systematic review of in vivo studies.
Systematic review of in vivo studies evaluating the anti-cancer activities of olive oil secoiridoid phenols. The review included 16 animal studies and 5 human intervention trials, with most animal studies confirming the ability of these compounds to inhibit carcinogenesis. Human trials showed mixed results on the preventive effect on oxidative DNA damage.
Association of hydroxytyrosol enriched olive oil with vascular function in chronic coronary disease.
Prospective, crossover, double-blind, placebo-controlled trial in 30 chronic coronary artery syndrome patients comparing hydroxytyrosol-enriched olive oil to placebo. Treatment improved endothelial, arterial, and LV diastolic function and reduced oxidative and inflammatory markers compared to baseline.
The Effect of a Hydroxytyrosol-Rich, Olive-Derived Phytocomplex on Aerobic Exercise and Acute Recovery.
RCT of 29 recreationally active participants consuming a hydroxytyrosol-rich olive-derived phytocomplex (OliPhenolia) or placebo for 16 days. OliP reduced exercise onset time constant, improved running economy at lactate threshold, and decreased perceived exertion. Modest improvements in acute recovery were observed, though time to exhaustion was not significantly different from placebo.
Oral Bioavailability and Metabolism of Hydroxytyrosol from Food Supplements.
A randomized, controlled, blinded, cross-over study investigated the bioavailability and metabolism of hydroxytyrosol (HT) from olive-derived watery supplements in 12 healthy volunteers. The study found that HT is bioavailable and its bioavailability increases with the administered dose, with maximum plasma concentrations peaking 30 minutes after intake. The results suggest potential benefits of HT supplements for protection against oxidative stress and cardiovascular risk.
Effect of Long-Term Hydroxytyrosol Administration on Body Weight, Fat Mass and Urine Metabolomics: A Randomized Double-Blind Prospective Human Study.
This randomized double-blind prospective study investigated the effect of hydroxytyrosol (HT) on obesity in 29 women with overweight/obesity over six months. Significant weight and visceral fat mass loss were observed in the group receiving the maximum HT dosage after 4 weeks, with attenuation at 12 and 24 weeks. HT was safe and well-tolerated.
The Impact of a Natural Olive-Derived Phytocomplex (OliPhenolia) on Exercise-Induced Oxidative Stress in Healthy Adults.
This study investigated the effects of OliPhenolia, an olive-derived phytocomplex rich in hydroxytyrosol, on exercise-induced oxidative stress in healthy adults. The study found that OliPhenolia demonstrated modest antioxidant effects, with increased glutathione levels and reduced superoxide dismutase activity post-exercise, suggesting potential benefits for acute exercise recovery.
Positive postprandial glycaemic and appetite-related effects of wheat breads enriched with either α-cyclodextrin or hydroxytyrosol/α-cyclodextrin inclusion complex.
RCT with 10 healthy adults testing wheat bread enriched with α-cyclodextrin or hydroxytyrosol/α-cyclodextrin complex. Both enriched breads were low GI foods and reduced glucose, insulin, and GLP-1 responses. The hydroxytyrosol complex showed additional positive effects on postprandial glycaemia and satiety.
Pharmacokinetics and bioavailability of hydroxytyrosol are dependent on the food matrix in humans.
A double-blind study with 20 volunteers investigated the pharmacokinetics and bioavailability of hydroxytyrosol when ingested through different food matrices. The study found that the food matrix significantly affects hydroxytyrosol's plasma concentrations and urinary contents, with extra virgin olive oil providing the highest bioavailability.
Supplementation with Hydroxytyrosol and Punicalagin Improves Early Atherosclerosis Markers Involved in the Asymptomatic Phase of Atherosclerosis in the Adult Population: A Randomized, Placebo-Controlled, Crossover Trial.
A randomized, placebo-controlled, crossover trial evaluated the effects of hydroxytyrosol and punicalagin supplementation on early atherosclerosis markers in middle-aged adults. The supplement improved endothelial function, reduced oxLDL levels, and decreased blood pressure, particularly in individuals with altered parameters.
The Antioxidant Effects of Hydroxytyrosol and Vitamin E on Pediatric Nonalcoholic Fatty Liver Disease, in a Clinical Trial: A New Treatment?
RCT of 80 adolescents with biopsy-proven NAFLD testing the efficacy of hydroxytyrosol and vitamin E. The treatment group showed decreased insulin resistance, triglyceride levels, oxidative stress parameters, and steatosis grade, suggesting potential benefits for NAFLD-related liver damage.
Chondroprotective Properties of Human-Enriched Serum Following Polyphenol Extract Absorption: Results from an Exploratory Clinical Trial.
Exploratory clinical trial investigating the osteoarticular benefits of a grapeseed and olive extract (OPCO) containing hydroxytyrosol and procyanidins. The study validated the anti-inflammatory and chondroprotective properties of the extract in vitro and confirmed these effects at a clinical level using an ex vivo methodology.
Antioxidant Effects of a Hydroxytyrosol-Based Pharmaceutical Formulation on Body Composition, Metabolic State, and Gene Expression: A Randomized Double-Blinded, Placebo-Controlled Crossover Trial.
This randomized double-blinded, placebo-controlled crossover trial evaluated the effects of 15 mg/day hydroxytyrosol in healthy volunteers over 3 weeks. The study found significant increases in oxidation biomarkers and reductions in nitrite, nitrate, and malondialdehyde levels. Body fat mass percentage, suprailiac skinfold, and weight were significantly reduced, indicating changes in body composition and modulation of antioxidant profile and gene expression related to inflammation and oxidative stress.
Transcriptomics and the Mediterranean Diet: A Systematic Review.
Systematic review of the influence of the Mediterranean diet on transcriptomes, focusing on the effects of virgin olive oil and its components. Monounsaturated fatty acid-rich diets and olive oil phenolic compounds prevent inflammatory gene expression, with compounds like tyrosol and hydroxytyrosol affecting cell cycle expression.
Hydroxytyrosol supplementation modulates the expression of miRNAs in rodents and in humans.
The study investigated the effects of hydroxytyrosol (HT) supplementation on miRNA expression in rodents and humans. HT modulated the expression of several miRNAs in mice and confirmed the modulation of one miRNA in healthy volunteers in a randomized, double-blind, placebo-controlled trial. HT administration also increased triglyceride levels, suggesting potential health implications.
Twelve-month consumption of a polyphenol extract from olive (Olea europaea) in a double blind, randomized trial increases serum total osteocalcin levels and improves serum lipid profiles in postmenopausal women with osteopenia.
Double-blind, placebo-controlled RCT of 64 postmenopausal women with osteopenia, testing 250 mg/day olive extract plus calcium versus calcium alone for 12 months. The treatment group showed increased serum osteocalcin levels, stable lumbar spine BMD, and improved lipid profiles with decreased total and LDL cholesterol.
One-week administration of hydroxytyrosol to humans does not activate Phase II enzymes.
Double-blind, randomized, placebo-controlled study tested hydroxytyrosol (HT) at doses of 5 and 25mg/d on Phase II enzyme expression in humans. HT was well tolerated but did not significantly modify Phase II enzyme expression or affect cardiovascular surrogate markers.
Double-blind placebo-controlled trial of hydroxytyrosol of Olea europaea on pain in gonarthrosis.
Double-blind placebo-controlled trial investigating the effect of hydroxytyrosol on pain in patients with gonarthrosis. Hydroxytyrosol administration resulted in significant improvement in pain measurement indices compared to placebo.
Bioavailability of the phenolic compounds of the fruits (drupes) of Olea europaea (olives): impact on plasma antioxidant status in humans.
The study examined the bioavailability of olive polyphenols and their impact on plasma antioxidant status in healthy volunteers. Olive polyphenols were absorbed and metabolized, increasing plasma antioxidant potential and levels of tyrosol and hydroxytyrosol.
Is dopamine behind the health benefits of red wine?
The study examined the pharmacokinetics of hydroxytyrosol in humans, comparing its disposition from red wine and olive oil. Despite different doses, urinary recoveries of hydroxytyrosol were higher after red wine administration, suggesting an interaction between ethanol and dopamine leading to hydroxytyrosol formation.
Immunotherapy with an extract of Olea europaea quantified in mass units. Evaluation of the safety and efficacy after one year of treatment.
RCT evaluating the safety and efficacy of specific immunotherapy (SIT) with Olea europaea extract in patients with rhinoconjunctivitis and asthma monosensitized to olive pollen. The active group showed significant improvements in nasal and bronchial symptoms, decreased reactivity, and reduced medication use compared to the control group.
Cardiovascular benefits of tyrosol and its endogenous conversion into hydroxytyrosol in humans. A randomized, controlled trial.
Randomized, crossover, controlled study in 33 individuals at cardiovascular risk assessing tyrosol's conversion to hydroxytyrosol and its cardiovascular benefits. Tyrosol supplementation improved endothelial function, increased plasma HDL-cholesterol and antithrombin IIII, and decreased plasma homocysteine, endothelin 1, and certain gene expressions.
Effects of postprandial hydroxytyrosol and derivates on oxidation of LDL, cardiometabolic state and gene expression: a nutrigenomic approach for cardiovascular prevention.
RCT evaluating the acute effects of 25g phenols-rich extra virgin olive oil (p-EVOO) in healthy volunteers. Significant reductions in oxidized LDL, malondialdehyde, triglycerides, and visceral adiposity index were observed, along with upregulation of genes related to oxidative stress and inflammation.
Generation of the Antioxidant Hydroxytyrosol from Tyrosol Present in Beer and Red Wine in a Randomized Clinical Trial.
RCT investigating the bioconversion of tyrosol (TYR) to hydroxytyrosol (HT) in 20 healthy subjects after consuming beer and red wine. The study found that red wine triggered the highest increase in TYR recovery, and all beers showed increased HT production, confirming TYR to HT biotransformation. The conversion rate was influenced by sex, genetics, and matrix components.
Impact of a Proprietary Standardized Olive Fruit Extract (SOFE) on Cardio-Ankle Vascular Index, Visual Analog Scale and C-Reactive Protein Assessments in Subjects with Arterial Stiffness Risk.
This double-blind, placebo-controlled study assessed the impact of a proprietary standardized olive fruit extract (SOFE) on arterial stiffness in subjects at risk. Group 2, receiving 500 mg SOFE, showed the largest reduction in CAVI scores and a significant decrease in triglyceride levels, suggesting improved arterial elasticity and potential cardiovascular benefits. No significant changes were observed in C-reactive protein levels.
Hydroxytyrosol supplementation increases vitamin C levels in vivo. A human volunteer trial.
RCT investigating the effects of hydroxytyrosol supplementation in 14 volunteers with mild hyperlipidemia over 8 weeks. Hydroxytyrosol was found to be safe and increased vitamin C levels two-fold, indicating a potential antioxidant function.
Ethanol induces hydroxytyrosol formation in humans.
Double-blind, randomized, crossover, controlled study with 24 healthy male volunteers to assess the effect of ethanol dose on hydroxytyrosol formation. Urinary excretion of hydroxytyrosol and tyrosol increased with ethanol dose, indicating a shift in dopamine metabolism towards hydroxytyrosol production.
Impact of olive oil phenolic concentration on human plasmatic phenolic metabolites.
Randomised cross-over study with 12 healthy volunteers assessing the pharmacokinetics of phenolic biological metabolites from phenol-enriched virgin olive oils. A dose-dependent response of phenol conjugate metabolites in human plasma was observed, with hydroxytyrosol sulfate as the main phenolic metabolite.
Postprandial LDL phenolic content and LDL oxidation are modulated by olive oil phenolic compounds in humans.
Cross-over study with 12 healthy male volunteers examining the effect of olive oil phenolic compounds on postprandial oxidative stress and LDL antioxidant content. Higher phenolic content in olive oil was associated with increased phenolic compounds in LDL and reduced LDL oxidation.
Bioavailability of phenolic compounds from olive oil and oxidative/antioxidant status at postprandial state in healthy humans.
RCT with 12 healthy male volunteers assessing the bioavailability of olive oil phenolic compounds and their effects on postprandial oxidative stress and blood lipids. Tyrosol and hydroxytyrosol were absorbed in a dose-dependent manner. No significant postprandial lipemia or increase in oxidation markers was observed. Glutathione peroxidase activity decreased after low phenolic content olive oil ingestion, but not after moderate and high phenolic content oils.
Tyrosol and hydroxytyrosol are absorbed from moderate and sustained doses of virgin olive oil in humans.
The study investigated the absorption of tyrosol and hydroxytyrosol from moderate and sustained doses of virgin olive oil in seven healthy volunteers. An increase in 24-hour urine levels of these compounds was observed after both single and sustained doses, suggesting their potential as biomarkers of virgin olive oil intake.
Potential treatment of atopic dermatitis: tolerability and safety of cream containing nanoparticles loaded with hydrocortisone and hydroxytyrosol in human subjects.
RCT assessing the safety and tolerability of a cream containing nanoparticles loaded with hydrocortisone and hydroxytyrosol on healthy human skin. The study found no significant local irritation, redness, or systemic toxicity after 28 days of application, suggesting the cream is safe and well-tolerated.
Health benefits of olive oil and by-products and possible innovative applications for industrial processes
This review discusses recent studies on the health benefits and industrial applications of olive oil and its by-products. It highlights bioactive compounds like hydroxytyrosol and oleuropein, which have been proposed for various uses, including as food additives and in bioremediation, while also noting their potential to reduce the risk of chronic diseases.
A combination of hydroxytyrosol, omega-3 fatty acids and curcumin improves pain and inflammation among early stage breast cancer patients receiving adjuvant hormonal therapy: results of a pilot study.
This pilot study evaluated the effects of a combination of hydroxytyrosol, omega-3 fatty acids, and curcumin on inflammation and pain in post-menopausal breast cancer patients receiving adjuvant hormonal therapies. CRP levels and pain scores decreased during the 1-month therapy, with the greatest CRP reduction in subjects with the highest baseline levels. No significant adverse events were reported.